Weather balloons are used to take important meteorological measurements in the atmosphere. MeteoSwiss takes two measurements a day in Payerne. Anyone who finds a weather balloon can send the probe back so that the various composite materials can be separated and disposed of correctly.
Weather balloons are used to release radiosondes into the atmosphere. The probes have various sensors and a transmitter that sends the collected data back to Earth. MeteoSwiss releases a weather balloon twice a day: From Monday to Friday, the balloons are launched manually at noon, and automatically at the same time at weekends; the second launch at 11 pm is always automatic. The sounding station is located in Payerne, where data from the atmosphere have been collected since the 1940s.
The hydrogen-filled weather balloons ascend at a speed of around five metres per second, taking approximately two hours to reach an altitude of 30-35 km.
The radiosondes measure air pressure, temperature and humidity. Their exact position is recorded using a GPS system, from which the altitude, wind speed and wind direction can be determined. During the ascent, measurements are taken every second and transmitted to the ground-level weather station in Payerne. Weather balloons are thus able to provide an accurate picture of the current state of the individual air layers. The data obtained in this way are of great importance for weather forecasts and climate research.
Since air pressure decreases with altitude, a weather balloon expands as it rises. When it reaches a certain altitude (around 35 kilometres), it bursts. The radiosonde then floats back to earth with the help of a parachute. Anyone who discovers a probe outdoors is asked to take it home with them. A label on the probe gives a website URL with instructions for returning the probe to MeteoSwiss, where its components will be recycled.